Merge pull request strongloop#3934 from strongloop/fix/crash-in-verifyUserRelations

fix: resolve customAccessToken warning error that causes app to crash

Author: bajtos

lib/application.js

@@ -497,8 +497,10 @@ app._verifyAuthModelRelations = function() {
   function verifyUserRelations(Model) {
     const hasManyTokens = Model.relations && Model.relations.accessTokens;
 
+    const relationsConfig = Model.settings.relations || {};
+    const hasPolyMorphicTokens = (relationsConfig.accessTokens || {}).polymorphic;
     // display a temp warning message for users using multiple users config
-    if (hasManyTokens.polymorphic) {
+    if (hasPolyMorphicTokens) {
       console.warn(
         'The app configuration follows the multiple user models setup ' +
           'as described in http://ibm.biz/setup-loopback-auth',
@@ -508,7 +510,6 @@ app._verifyAuthModelRelations = function() {
 
     if (hasManyTokens) return;
 
-    const relationsConfig = Model.settings.relations || {};
     const accessTokenName = (relationsConfig.accessTokens || {}).model;
     if (accessTokenName) {
       console.warn(